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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
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Visible-Light-Promoted C4-Selective Phosphorylation of Pyridine and Quinoline Derivatives
Peng-Cheng Cui1, Zheng-Chun Yin1, Guan-Wu Wang1,2
1Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P.R. China.
Organic Letters
|April 10, 2023
Summary
Visible light enables selective C4-phosphorylation of pyridine and quinoline derivatives. This new method offers a regioselective route to important compounds via a radical pathway under mild conditions.
Area of Science:
- Organic Chemistry
- Photocatalysis
- Heterocyclic Chemistry
Background:
- Pyridine and quinoline derivatives are crucial scaffolds in medicinal chemistry and materials science.
- Direct functionalization of these heterocycles, particularly at the C4 position, remains challenging.
- Existing methods often require pre-functionalized substrates or harsh reaction conditions.
Purpose of the Study:
- To develop a novel visible-light-promoted method for the direct C4-phosphorylation of unprefunctionalized pyridine and quinoline derivatives.
- To establish a regioselective and efficient protocol for accessing C4-phosphorylated heterocycles.
- To investigate the reaction mechanism and scope.
Main Methods:
- Utilizing visible light as the energy source for photocatalysis.
- Employing a Minisci-type radical reaction strategy.
- Performing cross-dehydrogenation coupling under mild reaction conditions.
Main Results:
- Achieved C4-selective phosphorylation of a range of pyridine and quinoline derivatives.
- Demonstrated good functional group tolerance.
- Obtained moderate to good yields of the desired C4-phosphorylation products.
- Mechanistic studies confirmed a radical pathway.
Conclusions:
- The developed visible-light-promoted protocol provides a facile and regioselective method for C4-phosphorylation of important N-heterocycles.
- This approach offers a valuable tool for synthesizing functionalized pyridine and quinoline derivatives under mild and sustainable conditions.
- The radical pathway provides new insights into the reactivity of these heterocyclic systems.
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